Image processing apparatus, image processing method and program

ABSTRACT

A density adjustment method for adjusting a density of a diagnostic image, having the steps of; exposing an image; developing the latent image; measuring a density of the developed image; creating a lookup table for relating the diagnostic image data and amount of exposure so as to form a density specified by the diagnostic image data; and correcting at least one of an exposure condition and a development condition to ensure that the next film has the optimized density, based on the difference between the measured density of a partial area of the film, and a density for comparison; wherein, a density of a prescribed area in a test exposure image is used as the density for comparison; while the exposure amount is used for exposing the partial area of the film at the time of forming a diagnostic image.

BACKGROUND OF THE INVENTION

The present invention relates to an image processing apparatus, an imageprocessing method and a program, and particularly to an image processingapparatus, an image processing method and a program that provideappropriate density in a finished film when an image is formed thereon.

PRIOR ART

In the prior art laser imager (image processing apparatus) for medicaltreatment, a diagnostic image is represented in density gradation. Thishas created a strong demand for a basic function of outputting alwaysstable density, and various measures have been taken to ensure stabledensity.

The laser imager for medical treatment has a so-called calibrationfunction of controlling the image formation portion to ensure that thedigital or video signal sent from each diagnostic apparatus or imagingapparatus has a constant density on a film.

Constant density is ensured immediately after calibration has beencarried out, but density is subjected to changes for various reasonswith the lapse of time after calibration. The heat development processis known to be easily changed.

For example;

(1) Change in exposure system due to temperature rise in an apparatus;

(2) Change in characteristics of heat development process such astemperature rise in heat development cooling/transfer section caused bysuccessive film processing;

(3) Change in sensitivity characteristics of the film stored in anapparatus;

(4) Change in the heat development drum characteristics due todeposition of fatty acid caused by successive film processing;

(5) Use of film different in heat development characteristics.

Sometimes a so-called density patch method is used. In this method, thedensity of a finished film having been exposed and developed is measuredin order to compensate for these changes. Then compensation is appliedto the next print. One of the known techniques according to this densitypatch method is the laser recoding apparatus (image processingapparatus) where the density of the film having been heat developed ismeasured, and the result of measurement is fed back to the intensity oflaser beam. (This is disclosed in the Official Gazette of Tokkai249138/1987)

In this density patch method, a rectangular area of about 5×10 mm at apredetermined position of a film is exposed at a predetermined lightintensity, and the developed density of this area is measured. Based onthe difference from the density that should be obtained (hereinafterreferred to as “density for comparison”), the exposure amount and/orheat development conditions are changed to ensure the optimum densityfor the subsequent prints.

Accordingly, if an incorrect value is used for this density forcomparison, a compensation system will determine that image density isinappropriate even if a process system reproduces an appropriate image(density). This will result in excessive or insufficient density.

The exposure and heat development systems contain causes for variationfor each apparatus, and it is not preferred to use a constant value forthe density for comparison.

PROBLEM TO BE SOLVED BY THE INVENTION—1

The first problem of the present invention is how to provide a densityadjustment method that can keep the image density of the same diagnosticimage signals within the scope of almost the same density, even iffluctuation has occurred to the characteristics of the exposure anddevelopment systems or a difference has occurred to the filmcharacteristics in formation of a diagnostic image.

PROBLEM TO BE SOLVED BY THE INVENTION—2

The present inventors have been led to the present invention by findingout that the problem is caused by the following reasons: (1) The patchportion for measuring the finished density for obtaining the differencefrom the density for comparison is formed at the tip of a film so that awhole image will not be adversely affected; (2) the posture of the filmseparated from a heating drum and moving toward a cooling/transfersection is not constant for each machine, and fluctuation is also causedby the change in the drum heating characteristics (developmentcharacteristics) resulting from the use of a drum (this phenomenon isconspicuous due to a soiled surface especially in the case of a drumwith silicon layer provided on the surface); and (3) the sensitivity onthe tip of the film and that on the other portion may be different inthe case of films A and B of different types, as shown in FIG. 8.

Thus, the second problem of the present invention is how to provide animage processing apparatus, an image processing method and a programwherein, even if there is any fluctuation in an image processingapparatus or films of different types (film characteristics) are used,the density value for comparison is automatically corrected using themeasured density value of the patch portion immediately aftercalibration, whereby the default value is automatically corrected andthe finished film is adjusted to have an appropriate density.

PROBLEM TO BE SOLVED BY THE INVENTION—3

In the aforementioned compensation system, comparatively stable imagedensity is obtained if power is turned on at all times. However, ifpower is turned off and the operation is resumed after that, anappropriate image has not been obtained in some cases. For example,assume that the system is used for medical diagnosis, and a medicaldiagnostic image has to be created when the medical treatment facilityis closed. Also assume that creation of a diagnostic print is completedon Friday. Based on the final print on this date, the compensationamount for the next print is stored, and printing is carried out basedon the compensation amount. Diagnostic printing must be restarted onMonday of the following week. In such cases, stable density has not beenobtained so far, according to the prior art. To solve this problem, theapparatus has been kept turned on even on Saturday and Sunday when theoffice is closed. This prior art method, however, is not recommendedfrom the viewpoint of energy saving.

When power cannot be kept turned on by all means for the reason ofsecurity management, the only way is to restart calibration. This hasresulted in excessive film consumption, according to the prior art.

The present inventors have been led to the present invention by findingout that the aforementioned problem is caused by the fact that thecharacteristics of the process system such as an exposure system forformation of a latent image or a heat development system forvisualization of a latent image are changed in response to the turningon/off of power.

The third problem of the present invention is how to provide an imageprocessing apparatus, an image processing method and a programcharacterized in that, even if power is turned off freely, the image ofappropriate density can be outputted, without the need of unwantedconsumption of films through calibration at every turning on of power,whereby energy is saved and a film is processed to have an appropriatedensity without wasting a film.

Other problems of the present invention will be apparent from thefollowing description:

SUMMARY OF THE INVENTION

To achieve the aforementioned objects, a density adjustment methodaccording to the present invention comprises:

an exposure step of forming an image by exposure of a film, based on thetest exposure data or diagnostic image signal;

a step of developing the aforementioned latent image exposed and formed;

a step of measuring the density of the aforementioned developed image;

a step of creating a lookup table for relating the image signal andamount of exposure so as to reproduce the density specified by thediagnostic image signal, based on the aforementioned test exposure dataand the measured density of the image formed on the film by the testexposure data; and

a step of correcting at least one of the exposure condition in theaforementioned exposure step and development condition in theaforementioned development step to ensure that the next film will havethe optimized density, based on the difference between the measureddensity value obtained by exposing a partial area of the film in forminga diagnostic image by the aforementioned diagnostic image signal and bymeasuring the density of the partial area of the film, and the densityvalue for comparison corresponding to the aforementioned predeterminedamount of exposure.

This density adjustment method is further characterized in that thedensity of a predetermined area exposed based on the aforementioned testexposure data is measured, and this density value is used as theaforementioned density value for comparison; at the same time, expossureis carried out in the same amount of exposure as that of thepredetermined area when the aforementioned partial area is exposed information of a diagnostic image.

According to this density adjustment method, a partial area is exposedin a predetermined amount of exposure, and the measured density value ofthe area exposed in a predetermined amount of exposure in calibrationpreviously carried out—not a preset fixed value—is used as the densityvalue for comparison when correcting at least one of the exposurecondition and development condition. At the same time, a predeterminedamount of exposure in the partial area is kept the same as that of theaforementioned predetermined area. Thus, even if fluctuation incharacteristics has occurred to the exposure system and developmentsystem subsequent to calibration or even if a difference has occurred tofilm characteristics, more accurate compensation for image density canbe achieved, and the image density of the same diagnostic image signalcan be kept within the scope of almost the same density. Further, themeasurement of the density for density value for comparison can beautomatically performed simultaneously with the calibration.Accordingly, only one sheet of film is used, and this provides aneconomical advantage.

In the predetermined area conforming to the aforementioned densityadjustment method, it is preferred to use the portion where the densityis 1.0 through 2.0. In the image exposed according to the aforementionedtest exposure data, the predetermined area at the tip of the film ispreferred to be used for the measurement of density. It is alsopreferred that the partial area in the formation of the diagnostic imagebe provided at the tip of the film.

The other density adjustment method according to the present inventioncomprises:

an exposure step of forming an image by exposure of a film, based on thetest exposure data or diagnostic image signal;

a step of developing the aforementioned latent image exposed and formed;

a step of measuring the density of the aforementioned developed image;

a step of creating a lookup table for relating the image signal andamount of exposure so as to reproduce the density specified by thediagnostic image signal, based on the aforementioned test exposure dataand the measured density of the image formed on the film by the testexposure data; and

a step of correcting at least one of the exposure condition in theaforementioned exposure step and development condition in theaforementioned development step to ensure that the next film will havethe optimized density, based on the difference between the measureddensity value obtained by exposing the partial area of the film informing a diagnostic image by the aforementioned diagnostic image signaland by measuring the density of the partial area of the film, and thedensity value for comparison corresponding to the aforementionedpredetermined amount of exposure. This density adjustment method isfurther characterized in that, after creation of the lookup table, theamount of exposure to get a predetermined density is obtained from thelookup table, and the film is exposed in that amount of exposure. Thenthe density of the image is measured, and the density is used as thedensity for comparison. At the same time, the partial area of thesubsequent diagnostic images is exposed in the same amount of exposureas that amount.

According to this density adjustment method, a partial area is exposedin a predetermined amount of exposure, and the measured density value ofthe area exposed in a predetermined amount of exposure obtained from thelookup table created in calibration previously carried out—not a presetfixed value—is used as the density value for comparison when correctingat least one of the exposure condition and development condition. At thesame time, a predetermined amount of exposure in the partial area iskept the same as that of the aforementioned predetermined area. Thus,even if fluctuation in characteristics has occurred to the exposuresystem and development system subsequent to calibration or even if adifference has occurred to film characteristics, more accuratecompensation for image density can be achieved, and the image density ofthe same diagnostic image signal can be kept within the scope of almostthe same density. Further, the amount of exposure can be obtained fromthe lookup table in such a way as to maintain the density area (e.g.D=1.0) sensitive to the fluctuation in characteristics aftercalibration. This improves the accuracy of compensation based on thedifference between the measured density value of the partial area anddensity value for comparison. Further, both the amount of exposure inthe partial area and that in the diagnostic image are determined via thelookup table, thereby simplifying the circuit configuration and dataprocessing for determining the amount of exposure in a diagnostic image.

In the aforementioned density adjustment method, it is preferred to usethe density of 1.0 through 2.0. In the image exposed according to theaforementioned test exposure data, the density in the predetermined areaat the tip of the film is preferred to be used as the density value forcomparison. In this case, it is preferred that density in theaforementioned predetermined area be measured several times and anaverage of these measurements be used as the density value forcomparison.

Further, the other density adjustment method according to the presentinvention comprises:

an exposure step of forming an image by exposure of a film, based on thetest exposure data or diagnostic image signal;

a step of developing the aforementioned latent image exposed and formed;

a step of measuring the density of the aforementioned developed image;

a step of creating a lookup table for relating the image signal andamount of exposure so as to reproduce the density specified by thediagnostic image signal, based on the aforementioned test exposure dataand the measured density of the image formed on the film by the testexposure data; and

a step of correcting at least one of the exposure condition in theaforementioned exposure step and development condition in theaforementioned development step to ensure that the next film will havethe optimized density, based on the difference between the measureddensity value obtained by exposing the partial area of the film informing a diagnostic image by the aforementioned diagnostic image signaland by measuring the density of the partial area of the film, and thedensity value for comparison corresponding to the aforementionedpredetermined amount of exposure. This density adjustment method isfurther characterized in that, after creation of the lookup table, theamount of exposure to get a predetermined density is obtained from thelookup table, and the film is exposed in that amount of exposure. Thenthe density of the image is measured, and the density is used as thedensity for comparison. At the same time, the partial area of thesubsequent diagnostic images is exposed in the same amount of exposureas that amount. This density adjustment method is still furthercharacterized in that, when a change has been made to at least one ofthe aforementioned film, development step, exposure step and densitymeasurement step, the aforementioned lookup table is created, and theaforementioned density value for comparison is set.

According to this density adjustment method, even if fluctuation incharacteristics has occurred to the exposure system and developmentsystem subsequent to calibration or even if a difference has occurred tofilm characteristics, more accurate compensation for image density canbe achieved, and the image density of the same diagnostic image signalcan be kept within the scope of almost the same density. When a statuschange has been made to at least one of the aforementioned film,development step, exposure step and density measurement step, a lookuptable is re-created, even if there is a sudden change in thecharacteristics before or after that, and the aforementioned densityvalue for comparison is set again. This feature eliminates the adverseeffect caused by change in film status, and ensures more accuratecompensation for the image density. The change in film status is definedas a change into the film of a different lot, and refers to the casewhere film development characteristics undergo sudden changes due to thelot.

For example, the aforementioned development process is carried out by aheating section containing the heating member for heating the film, anda cooling/transporting section for transferring the heated film whilecooling it. When the heating member has been replaced and/orcooling/transporting section has been subjected to maintenance, theaforementioned lookup table is created and density value for comparisonis set, thereby eliminating the adverse effect due to the fluctuation ofthe process conditions that have undergone sudden changes caused byreplacement of the heating member or replacement of a non-woven fabricsuch as a guide member coming in contact with the film of thecooling/transporting section.

In the aforementioned density adjustment method, it is preferred to usethe density of 1.0 through 2.0. The density in the predetermined area atthe tip of the film is preferred to be used as the density value forcomparison. In this case, it is preferred that density in theaforementioned predetermined area is measured several times and anaverage of these measurements be used as the density value forcomparison.

Furthermore, the other density adjustment method according to thepresent invention comprises:

an exposure step of forming an image by exposure of a film, based on thetest exposure data or diagnostic image signal;

a step of developing the aforementioned latent image exposed and formed;

a step of measuring the density of the aforementioned developed image;

a step of creating a lookup table for relating the image signal andamount of exposure so as to reproduce the density specified by thediagnostic image signal, based on the aforementioned test exposure dataand the measured density of the image formed on the film by the testexposure data; and

a step of compensating by correcting at least one of the exposurecondition in the aforementioned exposure step and development conditionin the aforementioned development step to ensure that the next film willhave the optimized density, based on the difference between the measureddensity value obtained by exposing the partial area of the film informing a diagnostic image by the aforementioned diagnostic image signaland by measuring the density of the partial area of the film, and thedensity value for comparison corresponding to the aforementionedpredetermined amount of exposure. This density adjustment method isfurther characterized in that the density of the predetermined areaexposed according to the aforementioned test exposure data is measuredand the measurement is used as the density value for comparison. At thesame time, exposure is carried out in the same amount of exposure asthat of the predetermined area when the aforementioned partial area isexposed in formation of a diagnostic image. When a status change hasbeen made to at least one of the aforementioned film, development step,exposure step and density measurement step, a lookup table isre-created, and the aforementioned density value for comparison is set.

According to this density adjustment method, even if fluctuation incharacteristics has occurred to the exposure system and developmentsystem subsequent to calibration or even if a difference has occurred tofilm characteristics, more accurate compensation for image density canbe achieved, and the image density of the same diagnostic image signalcan be kept within the scope of almost the same density. When a statuschange has been made to at least one of the aforementioned film,development step, exposure step and density measurement step, a lookuptable is re-created, even if there is a sudden change in thecharacteristics before or after that, and the aforementioned densityvalue for comparison is set again. This feature eliminates the adverseeffect caused by change in film status, and ensures more accuratecompensation for the image density. The change in film status is definedas a change into the film of a different lot, and refers to the casewhere film development characteristics undergo sudden changes due to thelot.

For example, the aforementioned development process is carried out by aheating section containing the heating member for heating the film, anda cooling/transporting section for transferring the heated film whilecooling it. When the heating member has been replaced and/orcooling/transporting section has been subjected to maintenance, theaforementioned lookup table is created and density value for comparisonis set, thereby eliminating the adverse effect due to the fluctuation ofthe process conditions that have undergone sudden changes caused byreplacement of the heating member or replacement of a non-woven fabricsuch as a guide member coming in contact with the film of thecooling/transporting section.

In the predetermined area conforming to the aforementioned densityadjustment method, it is preferred to use the portion where the densityis 1.0 through 2.0. In the image exposed according to the aforementionedtest exposure data, the predetermined area at the tip of the film ispreferred to be used for the measurement of density. It is alsopreferred that the partial area in the formation of the diagnostic imagebe provided at the tip of the film.

The aforementioned second problem can be solved by the present inventioncharacterized by the following features:

(21) An image processing apparatus comprising:

an exposure section for forming an image by exposure of a film, based onthe test exposure data or diagnostic image signal;

a development section for developing and visualizing the exposed film;

a measuring section for measuring the density of the film having beenexposed by the aforementioned exposure section and developed by thedevelopment section;

a calibration section for creating a lookup table for relating the imagesignal and amount of exposure so as to reproduce on the film the densityspecified by the diagnostic image data, based on the aforementioned testexposure data and the density of the image exposed and developed on thefilm according to the test exposure data, wherein the density of theimage has been measured by the aforementioned measuring section;

a compensation section for correcting exposure condition in theaforementioned exposure section so that the density of the next film isoptimized, based on the difference between the measured density valueobtained by exposing the partial area of the film so as to reproducepredetermined density based on the same lookup table as that ofdiagnostic image in forming a diagnostic image by the aforementioneddiagnostic image signal and by measuring the density of the partial areaof the film, and the density value for comparison corresponding to theaforementioned predetermined amount of exposure. This image processingapparatus is further characterized by containing a correction sectionfor correcting the density value for comparison based on the measureddensity value, prior to compensation by the compensation sectionsubsequent to creation of the lookup table by the calibration section.

(22) The image processing apparatus of item (21) characterized in thatthe aforementioned correction section corrects the density value forcomparison based on the measured density value, in the formation of animage within the predetermined time subsequent to creation of a lookuptable by the calibration section.

(23) The image processing apparatus of item (21) or (22) characterizedin that the density value for comparison is within the range of 1.0 to2.0.

(24) An image processing method comprising:

an exposure step for forming an image by exposure of a film, based onthe test exposure data or diagnostic image signal;

a development step for developing and visualizing the exposed film;

a measuring section for measuring the density of the film having beenexposed by the aforementioned exposure section and developed by thedevelopment section;

a calibration step for creating a lookup table for relating the imagesignal and amount of exposure so as to reproduce on the film the densityspecified by the diagnostic image data, based on the aforementioned testexposure data and the density of the image exposed and developed on thefilm according to the test exposure data, wherein the density of theimage has been measured by the aforementioned measuring section;

a compensation step for correcting exposure condition in theaforementioned exposure section so that the density of the next film isoptimized, based on the difference between the measured density valueobtained by exposing the partial area of the film so as to reproducepredetermined density based on the same lookup table as that ofdiagnostic image in forming a diagnostic image by the aforementioneddiagnostic image signal and by measuring the density of the partial areaof the film, and the density value for comparison corresponding to theaforementioned predetermined amount of exposure. This image processingmethod is further characterized by containing a correction step forcorrecting the density value for comparison based on the measureddensity value, prior to compensation by the compensation sectionsubsequent to creation of the lookup table by the calculated step.

(25) The image processing method of item (24) characterized in that theaforementioned correction step corrects the density value for comparisonbased on the measured density value, in the formation of an image withinthe predetermined time subsequent to creation of a lookup table by thecalibration section.

(26) The image processing method of item (24) or (25) characterized inthat the density value for comparison is within the range of 1.0 to 2.0.

(27) A program for using a computer to implement the image processingmethod described in any of claim 4 through claim 6, characterized bybeing incorporated in an image processing apparatus.

The third problem of the present invention can be solved by the presentinvention characterized by the following features:

(31) An image processing apparatus comprising:

an exposure section for forming an image as a latent image on a filmbased on image data, and for exposing a partial area of the film forimage formation with a predetermined exposure amount or with an outputexposure amount computed via a LUT with respect to a specified density;

a development section for developing and visualizing the exposed film;

a measuring section for measuring the density of the partial area of thedeveloped film;

a density control section for controlling the aforementioned exposuresection and/or development section so that the density of the next filmto be printed will be optimized, based on the difference between thepredetermined density value for comparison and the measured densityvalue, according to the result of measuring the density by theaforementioned measuring section;

a time monitoring section for monitoring the time when the power supplyto the image processing apparatus is suspended; and

a compensation section for correcting the control by the density controlsection, based on the down time monitored by the time monitoringsection.

(32) An image processing apparatus comprising:

an exposure section for forming an image as a latent image on a filmbased on image data, and for exposing a partial area of the film forimage formation with a predetermined exposure amount or with an outputexposure amount computed via a LUT with respect to a specified density;

a development section for developing and visualizing the exposed film;

a measuring section for measuring the density of the partial area of thedeveloped film;

a density control section for controlling the aforementioned exposuresection and/or development section so that the density of the next filmto be printed will be optimized, based on the difference between thepredetermined density value for comparison and the measured densityvalue, according to the result of measuring the density of a partialarea of the film by the aforementioned measuring section;

a temperature detection section for detecting the temperature of atleast one position on the image processing apparatus when power isturned on; and

a compensation section for correcting the control by the density controlsection, based on the temperature detected by the temperature detectionsection.

(33) The image processing apparatus of item (32) characterized in thatthe development section is equipped with a heating/transporting sectionand a cooling/transporting section, and the cooling/transporting sectionis equipped with the aforementioned temperature detection section.

(34) The image processing apparatus of item (32) or (33) characterizedin that the temperature detection section detects the temperature of theexposure section.

(35) An image processing apparatus comprising:

an exposure section for forming an image as a latent image on a filmbased on image data, and for exposing a partial area of the film forimage formation with a predetermined exposure amount or with an outputexposure amount computed via a LUT with respect to a specified density;

a development section for developing and visualizing the exposed film;

a measuring section for measuring the density of the partial area of thedeveloped film;

a density control section for controlling the aforementioned exposuresection and/or development section so that the density of the next filmto be printed will be optimized, based on the difference between thepredetermined density value for comparison and the measured densityvalue, according to the result of measuring the density of a partialarea of the film by the aforementioned measuring section;

a time monitoring section for monitoring the time when the power supplyto the image processing apparatus is suspended;

a temperature detection section for detecting the temperature of atleast one position on the image processing apparatus when power isturned on; and

a compensation section for correcting the control by the density controlsection, based on the down time monitored by the time monitoring sectionand the temperature detected by the temperature detection section.

(36) The image processing apparatus of item (35) characterized in thatthe development section is equipped with a heating/transporting sectionand a cooling/transporting section, and the cooling/transporting sectionis equipped with the aforementioned temperature detection section.

(37) The image processing apparatus of item (35) or (36) characterizedin that the temperature detection section detects the temperature of theexposure section.

(38) An image processing apparatus comprising:

an exposure section for forming an image as a latent image on a filmbased on image data;

a development section for developing and visualizing the exposed film;

a density control section for controlling the aforementioned exposuresection and/or development section in such a way as to offset changes ofcharacteristics in image formation, including those of theaforementioned exposure section and/or development section;

a time monitoring section for monitoring the time when the power supplyto the image processing apparatus is suspended; and

a compensation section for correcting the control by the density controlsection, based on the down time monitored by the time monitoringsection.

(39) An image processing method comprising:

an exposure step for forming an image as a latent image on a film basedon image data, and for exposing a partial area of the film for imageformation with a predetermined exposure amount or with an outputexposure amount computed via a LUT with respect to a specified density;

a development step for developing and visualizing the exposed film;

a measuring step for measuring the density of the developed film;

a density control step for controlling the aforementioned exposure stepand/or development step so that the density of the next film to beprinted will be optimized, based on the difference between thepredetermined density value for comparison and the measured densityvalue, based on the measurement of the density in a partial area of thefilm by the aforementioned measuring step;

a time monitoring step for monitoring the time when the power supply tothe image processing apparatus is suspended; and

a compensation step for correcting the control by the density controlstep, based on the down time monitored by the time monitoring step.

(40) An image processing method comprising:

an exposure step for forming an image as a latent image on a film basedon image data, and for exposing a partial area of the film for imageformation with a predetermined exposure amount or with an outputexposure amount computed via a LUT with respect to a specified density;

a development step for developing and visualizing the exposed film;

a measuring step for measuring the density of the developed film;

a density control step for controlling the aforementioned exposure stepand/or development step so that the density of the next film to beprinted will be optimized, based on the difference between thepredetermined density value for comparison and the measured densityvalue, based on the measurement of the density in a partial area of thefilm by the aforementioned measuring step;

a temperature detection step for detecting the temperature of at leastone position on the image processing apparatus when power is turned on;and

a compensation step for correcting the control by the density controlstep, based on the temperature detected by the temperature detectionstep.

(41) The image processing method of item (40) characterized in that thedevelopment step is equipped with a heating/transporting section and acooling/transporting section, and the cooling/transporting section isequipped with the aforementioned temperature detection step.

(42) An image processing method of item (39) or (40) characterized inthat the temperature detection step detects the temperature of theexposure step.

(43) An image processing method comprising:

an exposure step for forming an image as a latent image on a film basedon image data, and for exposing a partial area of the film for imageformation with a predetermined exposure amount or with an outputexposure amount computed via a LUT with respect to a specified density;

a development step for developing and visualizing the exposed film;

a measuring step for measuring the density of the developed film;

a density control step for controlling the aforementioned exposure stepand/or development step so that the density of the next film to beprinted will be optimized, based on the difference between thepredetermined density value for comparison and the measured densityvalue, based on the measurement of the density in a partial area of thefilm by the aforementioned measuring step;

a time monitoring step for monitoring the time when the power supply tothe image processing apparatus is suspended;

a temperature detection step for detecting the temperature of at leastone position on the image processing apparatus when power is turned on;and

a compensation step for correcting the control by the density controlstep, based on the down time monitored by the time monitoring step andthe temperature detected by the temperature detection step.

(44) The image processing method of item (43) characterized in that thedevelopment step is equipped with a heating/transporting section and acooling/transporting section, and the cooling/transporting section isequipped with the aforementioned temperature detection step.

(45) The image processing apparatus of item (43) or (44) characterizedin that the temperature detection step detects the temperature of theexposure step.

(46) An image processing method comprising:

an exposure step for forming an image as a latent image on a film basedon image data, and for exposing a partial area of the film for imageformation with a predetermined exposure amount or with an outputexposure amount computed via a LUT with respect to a specified density;

a development step for developing and visualizing the exposed film;

a density control step for controlling the aforementioned exposure stepand/or development step in such a way as to offset changes ofcharacteristics in image formation, including those of theaforementioned exposure step and/or development step;

a time monitoring step for monitoring the time when the power supply tothe image processing apparatus is suspended;

a compensation step for correcting the control by the density controlstep, based on the down time monitored by the time monitoring step.

(47) A program for using a computer to implement the image processingmethod described in any of claim 9 through claim 16, characterized bybeing incorporated in an image processing apparatus.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a front view representing the major sections of an imageprocessing apparatus as an embodiment of the present invention;

FIG. 2 is a block diagram representing the control system of an imageprocessing apparatus;

FIG. 3 is a diagram schematically showing the exposure section of theimage processing apparatus given in FIG. 1;

FIG. 4 is a flowchart representing a step for density adjustment in theimage processing apparatus given in FIG. 1;

FIG. 5 is a flowchart representing another step for density adjustmentin the image processing apparatus given in FIG. 1;

FIG. 6 is a flowchart representing still another step for densityadjustment in the image processing apparatus given in FIG. 1;

FIG. 7 is a cross sectional view of a film F schematically showing thechemical reaction in the film F during exposure in the image processingapparatus given in FIG. 1;

FIG. 8 is a cross sectional view, similar to FIG. 7, schematicallyshowing the chemical reaction in the film F during heating in the imageprocessing apparatus given in FIG. 1;

FIG. 9(a) is a diagram representing the relationship between the amountof light and density obtained in a calibration step as an embodiment ofthe present invention, and FIG. 9(b) is a diagram representing therelationship between the amount of light and density obtained again byrepeating the calibration step;

FIG. 10 is a front view of the major sections showing the guide memberarranged close to the heating drum in the cooling/transporting sectiongiven in FIG. 1;

FIG. 11 is a block diagram representing the functions of an imageprocessing apparatus for implementing the image processing method of thepresent invention;

FIG. 12 is a flowchart representing the processing of the imageprocessing apparatus given in FIG. 11;

FIG. 13 shows an example of the LUT;

FIG. 14 is a diagram representing the image area and partial area of afilm;

FIG. 15 is a diagram representing the differences in sensitivityaccording to film type;

FIG. 16 is a block diagram representing the functions of the embodimentof the image processing apparatus for implementing the image processingmethod of the present invention;

FIG. 17 is a flowchart representing the processing of the same;

FIGS. 18(a) through (c) show an example of the characteristicsfluctuation model inherent to the apparatus;

FIG. 19 is a diagram showing an example of compensation by acompensation section;

FIG. 20 is a block diagram representing the functions of the embodimentof the image processing apparatus for implementing the image processingmethod of the present invention;

FIG. 21 is a flowchart representing the processing of the imageprocessing apparatus given in FIG. 10;

FIGS. 22(a) and (b) show an example of the fluctuation ofcharacteristics caused by temperature;

FIG. 23 is a block diagram representing the functions of the secondembodiment of the image processing apparatus for implementing the imageprocessing method of the present invention; and

FIG. 24 is a flowchart representing the processing of the imageprocessing apparatus given in FIG. 23.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

The following describes the preferred embodiments of the presentinvention with reference to drawings:

FIG. 1 is a front view representing the major sections of an imageprocessing apparatus as an embodiment of the present invention. FIG. 2is a block diagram representing the control system of an imageprocessing apparatus, and FIG. 3 is a diagram schematically showing theexposure section of the image processing apparatus given in FIG. 1.

(First Embodiment of the Present Invention)

As shown in FIG. 1, an image processing apparatus 100 comprises:

a feed section 110 further including;

a first loading section 11 and a second loading section 12 for loading apackage containing a predetermined number of films as sheet-formed heatdevelopment photosensitive materials, and

a supply section 90 for transferring and supply each film for exposureand development;

an exposure section 120 for forming a latent image by exposing the filmfed from the feed section 110;

a development section 130 for heat development of the film with latentimage formed thereon; and

a densitometer 200 for getting information on density by measuring thedensity of the developed film. Films one by one are fed from the firstand second loading sections 11 and 12 by the supply section 90 andtransfer roller pairs 39, 40 and 141 in the arrow-marked direction (1)of FIG. 1.

As shown in FIG. 2, the image processing apparatus 100 is provided witha control section 99 for controlling the feed section 110, exposuresection 120, development section 130 and densitometer 200. The controlsection 99 receives the control signal from the aforementioned varioussections to control the entire system.

The following describes the exposure section 120 of the image processingapparatus 100 with reference to FIG. 3. As shown in FIG. 3, the exposuresection 120 uses a rotary polygon mirror 113 to deflect the laser lightL having a predetermined wavelength of 780 through 860 nm, therebyprovide main scanning on the film F. At the same time, it causes thefilm F to make a relative movement in approximately the horizontaldirection—a direction approximately at right angles with the directionof main scanning—with respect to laser light L, whereby sub-scanning isperformed so that laser light L is used to allow a latent image to beformed on the film F.

The following describes a concrete configuration with reference to theexposure section 120: In FIG. 3, upon receipt of the image signal S as adigital signal outputted from the image signal output apparatus 121, theimage signal S is converted into an analog signal by a digital-to-analogconverter 122, and is inputted into a modulation circuit 123. Based onsuch an analog signal, the modulation circuit 123 controls the driver124 of the laser light source 110 a and applies the modulated laserlight L from the laser light source 110 a. Further, the high frequencycomponent is superimposed on laser light through the modulation circuit123 and driver 124 by a high frequency superposition section 118,thereby preventing the interference fringe of the film from beingformed.

An acousto-optic modulator 88 is arranged between the lens 112 of theexposure section 120 and laser light source 110 a. This acousto-opticmodulator 88 is controlled and driven by an acousto-optic modulation(AOM) driver 89 based on the signal from the signal from thecompensation control section 71 for adjusting the amount of modulation.The compensation control section 71 controls the acousto-optic modulator88, based on the compensation signal from the control section 99, insuch a way as to ensure the optimum amount of modulation (ratio of theamount of outgoing light with respect to the amount of incoming light)at the time of exposure.

The laser light L emitted from the laser light source 110 a, wherein theamount of this light is adjusted to an optimum level by theacousto-optic modulator 88, passes through the lens 112, and is thenconverged in the vertical direction alone by a cylindrical lens 115. Thelight then enters the rotary polygon mirror 113 rotating in thedirection marked with arrow “A” of FIG. 3 as linear image perpendicularto the drive shaft of this rotary polygon mirror. The rotary polygonmirror 113 reflects and deflects the laser light L in the direction ofmain scanning. After passing through the fθ lens 114 including acylindrical lens composed of a combination of four lens, the deflectedlaser light L is reflected by the mirror 116 arranged in the directionof main scanning as an extension on the optical path, and main scanningis repeated in the direction of arrow “X” on the scanned surface 117 ofthe film F being transferred in the direction of arrow “Y” (beingsub-scanned) by the transfer apparatus 142. This causes the laser lightL to scan the entire surface of the scanned surface 117 of the film F.

The cylindrical lens of the fθ lens 114 is arranged to converge theincoming laser light L on the scanned surface only in the direction ofsub-scanning. The distance from the fθ lens 114 to the scanned surfaceof the film F is equal to the focal distance of the entire fθ lens 114.As can been seen, the cylindrical lens 115 and fθ lens 114 including thecylindrical lens are arranged in the exposure section 120, and laserlight L is converged in the direction of sub-scanning on the rotarypolygon mirror 113. Thus, even if planar inclination or shaft vibrationhas occurred to the rotary polygon mirror 113, the scanning position ofthe laser light L does not deviate in the direction of sub-scanning onthe scanned surface of the film F, thereby ensuring a scanning line ofregular pitch to be formed. The rotary polygon mirror 113 is moreadvantageous in scanning stability than the galvanometer mirror andother optical deflectors, for example. In the manner described above, alatent image in conformity to image signal S is formed on the film F.

The following describes the development section 130 andcooling/transporting section 150 of the image processing apparatus givenin FIG. 1: As shown in FIG. 1, the development section 130 contains adrum 14 capable of heating the film F while retaining it on the outerperiphery, and a multiple rolls 16 for retaining the film by gripping itwith the drum 14. The drum 14 incorporates a heater (not illustrated)and provides heat development of the film F by keeping the film F at atemperature above not less than a predetermined minimum heat developmenttemperature (for example, about 110° C.) for a predetermined time forheat development. This allows the aforementioned development section 120to form a visible image from the latent image formed on the film F. Theheater of the drum 14 is controlled by the control section 99, anddensity is adjusted by changing the heater temperature, hence,development temperature.

A transfer roller pair 144 and densitometer 200 are incorporated on theleft of the development section 130. Further, a cooling/transportingsection 150 for cooling the heated film is provided. The film F removedfrom the drum 14 is cooled by the cooling/transporting section 150 whilebeing fed to the position off to the lower right, as shown in the arrow(3) in FIG. 1. The densitometer 200 measures the density of the film Fwhile the transfer roller pair 144 carries the cooled film F. Then themultiple transfer roller pairs 144 further feed the film F, as indicatedby the arrow (4) in FIG. 1. The film is ejected into the ejection tray160 so that the film can be taken out of the top of the image processingapparatus 100.

FIG. 10 is a front view of the major sections showing the guide member21 arranged close to the heating drum 14 in the cooling/transportingsection 150 given in FIG. 1. As shown in FIG. 10, the guide member 21comprises a heat-insulated first member 22 of a non-woven fabricconstituting a guide surface 30 for guiding the film F, and a thermallyconductive second member 23 of aluminum or other metallic materialarranged integrally with the bottom surface of the first member 22. Inthe guide member 21, after the film indicated by a broken line in FIG.10 is transferred sandwiched between the heating drum 14 and guideroller 16, and is removed from the outer peripheral surface 14 a, thefilm F is guided by the guide surface 30.

The densitometer 200 of FIG. 1 is provided with a light emitting section200 a and a light receiving section 200 b. When the developed film istransferred between the light emitting section 200 a and light receivingsection 200 b, as described above, the light emitted from the lightemitting section 200 a is received by the light receiving section 200 bthrough the film, and density is measured according to the degree ofattenuation of the received light.

In the present embodiment, the development section 130, together withthe exposure section 120, is incorporated in the image processingapparatus 100, but it can be independent of the exposure section 120. Inthis case, it is preferred that there is a transfer section that feedsthe film F from the exposure section 120 to the development section 130.It is also preferred that the drum 14 is covered with a heat insulatingmaterial to ensure easier temperature control of the drum 14.

The following describes calibration in the present embodiment withreference to FIG. 9: FIG. 9(a) is a diagram representing therelationship between the amount of light when the film is exposed, anddensity measured after development. FIG. 9(b) is a diagram representingthe relationship between the amount of light and density obtained againby repeating the calibration step.

In the exposure section 120 of FIG. 3, the amount of exposure iscalculated using the lookup table (LUT) as a conversion table betweenthe density and amount of light inherent to the image processingapparatus at a certain point of time, in response to the image signalinputted into the exposure section 120 (signal for specifying thefinished density from an image signal output apparatus 121 of adiagnostic apparatus, etc.). For this purpose, the latent image of aso-called wedge pattern, where the amount of light is gradually changedon a tentative basis by a predetermined exposure pattern signal inputtedinto the exposure section 120, is formed on a film. The density of thedeveloped wedge pattern are measured, thereby creating a curve “a”representing the relationship between the amount of light and density asshown in FIG. 9(a). The step of creating the lookup table (LUT) in thisway is called calibration.

In the subsequent steps of image formation, the amount of light M iscalculated from the aforementioned lookup table, based on the density Dspecified by the image signal (=finished density specification), asshown in FIG. 9(a). This calculated amount of light is used to exposethe film, whereby the density of the finished film can be adjusted tothe specified level. As can been seen, the image signal is correlated tothe amount of exposure in the lookup table so as to reproduce thedensity specified by the diagnostic image signal.

If eclipse has occurred to part of the optical path because of thechange in alignment of the optical system in the exposure section 120due to impact or the like on the image processing apparatus proper,there will be a change in the amount of light reaching the film even ifcontrol is made to get the amount of light given in FIG. 9(a), with theresult that images with different densities will be formed in the phaseof forming a latent image. If the development conditions and filmcharacteristics are constant, the density of the finished film willbecome different. Accordingly, to maintain the density of the finishedfilm constant, it is necessary to change the LUT that represents therelationship between the density and the amount of light. This makes itnecessary to develop the latent image formed by the same exposurepattern signal and to measure the density of that pattern, therebycreating a curve “b” representing the relationship between the amount oflight and density as shown in FIG. 9(b) and re-creating the LUT.

As shown in FIG. 9(b), the amount of light M1 is calculated based on thedensity D specified by the image signal (=finished density signal) bythe LUT after recreation, and the film is exposed with this calculatedamount of light, whereby the density of the finished film can beadjusted to the specified level. As can been seen, the amount of lightnewly obtained from the re-created LUT becomes the amount of light to benewly controlled. It should be noted that exposure is performed in theamount of exposure M if the curve “a” is used unchanged when therelationship between the density and amount of exposure due to thechange in alignment of the optical system in the exposure section 120,for example, is changed as shown in curve “b”. As can be seen from FIG.9(b), the density of the finished film will be D1 that is lower than D.

Normally, there is a greater amount of variation in film characteristicsamong production lots, and a LUT is created every time a new filmpackage is loaded. Further, as the operation time of the heating drum 14is longer, heat development characteristics undergo changes due todeterioration of the heat transfer performance. In this case, thefinished density becomes different. If such changes are anticipated, theLUT must be re-created, as in the aforementioned case.

To put it more specifically, in the aforementioned calibration step,test exposure data signal is inputted as the image signal S of FIG. 3,and the film is exposed by the exposure section 120 according to apredetermined exposure pattern where the amount of exposure is changedfor each area and development is performed by the development section130, whereby the density in each area of the exposure pattern formed onthe film is measured by the densitometer 200. The relationship betweenthe measured density and the amount of exposure is obtained as shown inFIG. 9(a), thereby creating the LUT representing the relationshipbetween the specified density and amount of exposure. This LUT is storedin the memory of the compensation control section 71 of the exposuresection 120. In this way, calibration is performed.

When image signal S has been inputted from the image signal outputapparatus 121 into the exposure section 120 of FIG. 3, the laser light Lmodulated by the laser light source 110 a is applied, whereby the film Fis exposed to laser light, and a latent image is formed. In this case,the compensation control section 71 obtains the amount of exposure inresponse to the specified density in the image signal, from theaforementioned LUT. The compensation signal is fed back to theacousto-optic modulator 88 through the acousto-optic modulation (AOM)driver 89 in such a way that this amount of exposure is reached. Theamount of modulation is controlled by the acousto-optic modulator 88,whereby the density of the finished film can be adjusted to thespecified level.

The exposure pattern as the test exposure data includes an image to beexposed in a predetermined amount of light in multiple stages of about 5through 100 (e.g. 20 stages) by changing the position sequentially inthe direction of feed, and an image exposed in a predetermined amount ofexposure in multiple stages of about 5 through 100 (e.g. 20 stages) bychanging the position sequentially in a matrix form. It is also possibleto use a test image of other pattern.

As described above, calibration is carried out when a new film packageis loaded on the loading sections 11 and 12. Thus, even if there is abig variation in the film characteristics for each film package due tothe production lot, a LUT conforming to a particular film is created.This method allows exposure to be carried out with compensation made forvariations in the film characteristics.

Further, this method allows exposure to be carried out with compensationmade for variations because calibration is carried out at a propertiming to produce a LUT, even if there is a change in the filmsensitivity due to variations of temperature in the apparatus, theamount of laser light L is changed by the acousto-optic modulation (AOM)driver 89 and high frequency superposition section 118 being affected inthe exposure section 120, there is a change in the alignment of theoptical system in the exposure section 120, or there is a change in thecharacteristics of the heating drum 14.

Moreover, in the image forming apparatus 100 given in FIG. 1, an densityimage (patch image) for density management measuring about 5 by 10 mm isformed on the corner of the film tip under a certain condition in theexposure and development of a normal diagnostic image, therebycontrolling the amount of modulation of the laser light and optimizingthe density. To put it another way, a patch image is formed on thecorner of the film tip when a diagnostic image is formed, and thedensity of the patch image is measured by the densitometer 200. Themeasured density of the patch image is compared with the density valuefor comparison. If the difference in density exceeds a certain value,the compensation control section 71 provides control in such a way thatthe optimum amount of modulation can be obtained at the time of the nextfilm exposure.

In the density adjustment using the aforementioned patch image, themeasured density value obtained in the previous calibration—not thepreset fixed value—is used as the density value for comparison. In thismanner, the variation of density, resulting from the aforementioned (1)through (5) exhibiting a relatively gentle with-time variation after theLUT has been created in the step of calibration, is fed back to the heatdevelopment condition and exposure condition (amount of exposure) inorder to use the patch image-based compensation to offset this variationof density. This allows the finished density to be maintained with highaccuracy. To put it another way;

even if development density is changed after creation of the LUT due to:changes in the film sensitivity due to the influence of changes oftemperature in the apparatus; changes of characteristics in theacousto-optic modulation (AOM) driver 89 of the exposure section 120 andhigh frequency superposition section 118; and changes of characteristicsin the heating drum 14; and

even if a variation over a certain level has occurred, compensationbased on the difference from the density value for comparison is carriedout by the measurement of the patch image density. This method ensuresappropriate finished density to be maintained.

In the case of FIG. 6 (to be described later), if a relatively suddenchange of status in image processing is anticipated to take place, theLUT is re-created and the density value for comparison is also set againat the same time.

The following describes the operation of the image processing apparatus100 using the FIG. 4 with reference to FIGS. 1 through 3:

(Calibration)

The test exposure data signal stored in the memory such as the controlsection 99 is inputted into the exposure section 120 (S01), and the filmis fed in the directions (1) and (2) given in FIG. 1. Based on thisinput signal, film F is scanned by laser light in the exposure section120, and exposure is performed according to a predetermined exposurepattern (S02). The film F on which the latent image of the test imagehas been formed based on the predetermined exposure pattern further fedin the direction (2) given in FIG. 1 by the roller pair 142. The film isfurther fed into the development section 130 by the roller pair 143.Passing through the drum 14 and multiple rollers 16, the film F is fedin the direction of (3) while being heated on the periphery of the drum14 by the rotation of the drum 14. The film F is then heat-developed andthe latent image of the test image is visualized (S03).

In the next step, the film F with the visualized test image formedthereon is fed by the transfer roller pair 144 and the density of thetest image of the film F is read by the densitometer 200, therebymeasuring the density (S04). Further, the film F is fed in the direction(4) by the transfer roller pair 144 and is ejected into the ejectiontray 160 outside the apparatus 100. The density of the predeterminedarea exposed by the predetermined amount of exposure is measured in theaforementioned exposure step S02, and the measured density value isstored in the memory of the compensation control section 71 (S09). Thisdensity value is later used as a density value for comparison whencomparison is made with the measured density value of the patch image.It should be noted that the predetermined area to be exposed in thepredetermined amount of exposure is preferred to be the area on the filmtip.

The LUT is created from the relationship between the density and amountof exposure obtained from the aforementioned measurement as shown inFIG. 9(a), and is stored in the memory of the compensation controlsection 71 of the exposure section 120 (S05). In the manner describedabove, calibration is carried out by the test exposure data.

(Formation of Diagnostic Image)

As shown in FIG. 3, a diagnostic image signal is inputted as imagesignal S from the image signal output apparatus 121 in the exposuresection 120 (S06). The film F is subjected to laser exposure to form alatent image of the diagnostic image by applying the laser light Lmodulated from the laser light source 110 a via the digital-to-analogconverter 122, modulation circuit 123 and driver 124 (S07). In this stepof exposure, density compensation is made by the aforementioned LUT.

In the aforementioned step of exposure, the patch image is exposed onthe corner of the tip of the film F in the same amount of exposure asthat for the predetermined area where density is measured in theaforementioned calibration step S09, whereby the latent image of thepatch image is formed (S10).

As shown in FIG. 1, the film F is fed and heat-developed in thedevelopment section 130 to get the diagnostic image and patch image asvisible images (S08). The film F with the patch image formed on thecorner is further fed and the density of the patch image is measured bythe densitometer 200(S11). Then the film F is ejected to the ejectiontray 160 located at the outside of the image forming apparatus 100.

In the step of calibration (S09), the measured density value of thepredetermined area exposed in the same amount of exposure as that of thepatch image is used as a density value for comparison (S12) to get thedifference between the measured density value of the patch image and theaforementioned density value for comparison (S13). Based on thedifference in density, evaluation is made to determine whether or notcompensation should be made (S14). If the difference in density is abovea certain level, the compensation control section 71 allows the amountof compensation to be inputted into the memory in such a way that theoptimum amount of modulation can be gained in the next film exposure(S15).

Out of the predetermined area exposed in the predetermined amount ofexposure in the exposure step for calibration S02, the area whosedensity is from 1.0 through 2.0 is preferred to be used.

When the next diagnostic image data has been inputted (S06), the samestep as the above is followed. In the exposure step (S07), laserexposure is provided by the laser light modulated with considerationgiven to the aforementioned amount of compensation. Namely;

even if development density is changed due to:

changes in the film sensitivity due to the influence of changes oftemperature in the apparatus,

changes of characteristics in the acousto-optic modulation (AOM) driver89 of the exposure section 120 and high frequency superposition section118, and

changes of characteristics in the heating drum 14, and

even if a variation over a certain level has occurred, compensation fordensity is carried out in response to each situation, whereby adiagnostic image of appropriate density can be gained at all times.

As described above, according to the density adjustment method given inFIG. 4, the amount of exposure of the patch image is the same as thatwhen measured density is obtained in the immediately preceding step ofcalibration. The automatic reading of the measured density value gainedin the immediately preceding calibration step—not the predeterminedfixed value—can be used as the density value for comparison to becompared with the measured density value. Even if the variation hasoccurred to the characteristics of the exposure and development systemsof the exposure section 120 and development section 130, or differencehas occurred to the film characteristics, more accurate compensation forthe image density can be ensured every time such a trouble occurs, andthe image density of the same diagnostic image signal can be kept withinthe scope of almost the same density. The density measurement for thedensity value for comparison S09 can be performed automatically at thesame time as the density measurement S04 for calibration. Accordingly,only one film is used, and this provides an economical advantage.

The following shows another density adjustment method with reference tothe flowchart in FIG. 5: As shown in FIG. 4, calibration is performed asfollows: To put it another way, the test exposure data signal isinputted into the exposure section 120 (S21). Based on this signal, thefilm F is exposed according to the predetermined exposure patch (S22).The film F with the latent image of the test image formed thereon isheat-developed in the development section 130 (S23). The density ismeasured (S24) when the densitometer 200 reads the density of the testimage from the film F with the test image formed thereon. A LUT iscreated from the relationship between the density and amount of exposureobtained by this density measurement, and is stored in the memory of thecompensation control section 71 of the exposure section 120 (S25).

Then the amount of exposure for getting a predetermined density isobtained from the aforementioned LUT (S26), and the film is exposed(S27) and developed (S28) in this obtained amount of exposure. Thedensity of the image in the exposed area is measured and the measureddensity value is stored in the memory of the compensation controlsection 71 (S29). This measured density value is later used as thedensity value for comparison when comparison is made with the measureddensity value of the patch image (S30).

When the diagnostic image signal is inputted into the exposure section120 (S31), the film F is subjected to laser exposure to form a latentimage of the diagnostic image (S32), similarly to the case of FIG. 4. Inthis case, a patch image is formed on the corner of the film tip (S33)by exposure performed in the same amount of exposure as that obtained inthe aforementioned step S26. The film is then heat-developed by thedevelopment section 130 (S34) and the density of the patch image formedon the corner of the film F is measured by the densitometer 200 (S35).

Based on the density difference obtained from the measured density valueof the patch image and the density value for comparison obtained in theaforementioned step 30 (S36), evaluation is made to determine whether ornot compensation should be made (S37). If the difference in density isabove a certain level, the compensation control section 71 allows theamount of compensation to be inputted into the memory in such a way thatthe optimum amount of modulation can be gained in the next film exposure(S38).

Going back to the step 31, the same step as the aforementioned one isfollowed when the next diagnostic image signal has been inputted. In theexposure step S32, laser exposure is provided by the laser lightmodulated with consideration given to the aforementioned amount ofcompensation.

As described above, according to the density adjustment method given inFIG. 5, the value obtained by measuring the density of the image exposedin the amount of exposure got from the LUT created in the immediatelypreceding calibration step—not the predetermined fixed value—can be usedas the density value for comparison to be compared with the measureddensity value of the patch image. Accordingly, similarly to the case ofFIG. 4, even if the variation has occurred to the characteristics of theexposure and development systems of the exposure section 120 anddevelopment section 130, or difference has occurred to the filmcharacteristics, more accurate compensation for the image density can beensured every time such a trouble occurs, and the image density of thesame diagnostic image signal can be kept within the scope of almost thesame density.

In FIG. 4, the target density value is read by specifying the absoluteamount of light. So if there is a change in the developmentcharacteristics, compensation will be repeated for the difference in thepatch image density based on the finished area having the density ofabout D=0.5 where the sensitivity to the fluctuation in characteristicsis relative weak, even if the amount of light is specified so that thedensity area inherently sensitive to the fluctuation in characteristics(e.g. D=1.0) is gained. Accuracy is slightly inferior in this method. Bycontrast, in FIG. 5 the amount of light is calculated according to theLUT to ensure that sensitive density area (e.g. D=1) subsequent tocalibration will be maintained. This method improves the accuracy ofcompensation for the difference in temperature of the patch image.Further, the amount of exposure for the patch image and that fordiagnostic image are both determined through the LUT, therebysimplifying the circuit configuration and data processing fordetermining the amount of light for diagnostic image.

In FIG. 4, the amount of exposure of the patch image without passingthrough the LUT coexists with that of diagnostic image passing throughthe LUT. This complicates the circuit configuration and data processing.While only one sheet of film is used in FIG. 4, at least two sheets offilm (one for calibration and the other for measurement of the densityvalue for comparison) are required in FIG. 5.

The following shows still another density adjustment method withreference to the flowchart given in FIG. 6. The density adjustmentmethod in FIG. 6 is based on the same principle as that in FIG. 5.However, there will be a sudden change in the developmentcharacteristics when the drum 14 has been replaced orcooling/transporting section 150 has been subjected to maintenanceincluding replacement and cleaning in the image forming apparatus 100.So a lookup table is re-created, and the aforementioned density valuefor comparison to be compared with the measured density value of thepatch image is set again.

Calibration is performed in a manner similarly to the case of FIG. 5. Toput it another way, the test exposure data signal is inputted into theexposure section 120 (S41), and the film is exposed according to apredetermined exposure pattern (S42). Then the film is heat-developed inthe development section 130 (S43), and the density of the test image isread by the densitometer 200, thereby measuring the density (S44).

Based on the relationship between the density and amount of exposureobtained from this density measurement, a LUT is created and is storedinto the memory of the compensation control section 71 of the exposuresection 120 (S45).

From the aforementioned LUT, the amount of exposure is obtained to get apredetermined density (S46). The film is exposed (S47) and developed(S48) in this obtained amount of exposure. The density of the image inthe exposed area is measured and the measured density value is stored inthe memory of the compensation control section 71 (S49). This measureddensity value is later used as the density value for comparison whencomparison is made with the measured density value of the patch image(S50).

If such maintenance as replacement of the heating drum 14 or cleaning ofthe cooling/transporting section 150 is not performed in the imageforming apparatus 100 after the creation of the aforementioned LUT andsetting of the density value for comparison (S51), the diagnostic imagesignal will be inputted into the exposure section 120 (S52) and the filmF will be exposed (S53), similarly to the case of FIG. 5. In this case,the corner of the film tip is exposed in the same amount of exposure asthat obtained in the step S46, thereby forming a patch image (S54). Heatdevelopment is carried out in the development section 130 (S55) and thedensity of the patch image formed on the corner of the film F ismeasured by the densitometer 200 (S56).

Evaluation is made to determine (S58) whether or not compensation shouldbe made based on the density difference (S57) obtained from the measureddensity value of the patch image and density value for comparisonobtained in the step S50. If the difference in temperature is above acertain level, the compensation control section 71 allows the amount ofcompensation to be inputted into the memory in such a way that theoptimum amount of modulation can be gained in the next film exposure(S59).

The system goes back to the step S51. If such maintenance as replacementof the heating drum 14 or cleaning of the cooling/transporting section150 is performed in the image forming apparatus 100 (S51), the systemgoes back to the step S41 to follow the steps 41 through 45, wherebydensity value for comparison is set again.

As described above, according to the density adjustment method given inFIG. 6, even if the variation has occurred to the characteristics of theexposure and development systems of the exposure section 120 ordevelopment section 130, or difference has occurred to the filmcharacteristics, more accurate compensation for the image density can beensured every time such a trouble occurs, and the image density of thesame diagnostic image signal can be kept within the scope of almost thesame density, similarly to the case of FIG. 5. Further, this methodimproves the accuracy of compensation for the difference in density ofthe patch image, thereby simplifying the circuit configuration and dataprocessing for determining the amount of light for diagnostic image.

When the heating drum 14 has been replaced, the non-woven fabric of thefirst member 22 constituting the guide surface 30 of the guide member 21in the cooling/transporting section 150 has been replaced or thetransfer roller pair 144 of the guide surface 30 has been cleaned at thetime of maintenance of the image forming apparatus 100, thesecharacteristics are subjected to relatively sudden changes. After that,the LUT is re-created and the density value for comparison to becompared with the measured density value of the patch image is setagain. This procedure provides adequate compensation and offsets thechanges in characteristics caused by such maintenance work.

The predetermined density in the steps S26 and S27 in FIGS. 5 and 6 ispreferred to be in the range from 1.0 to 2.0.

It is preferred that the density value for measurement to get thedensity value for comparison be determined by carrying out measurementseveral times and taking an average of these measurements. This willprovide more accurate value.

Further, the density adjustment method in FIG. 6 consists of the methodgiven in FIG. 5, plus the step S51 of determining if the maintenanceshould be carried out or not. Similarly, the same effect as that in FIG.6 can be obtained by adding to the method given in FIG. 4 the step S51of determining if the maintenance should be carried out or not.

The following shows the latent image formation and heat development inthe film M as a photosensitive material for heat development as thepresent embodiment, with reference to FIGS. 7 and 8: FIG. 7 is a crosssectional view of a film F schematically showing the chemical reactionin the film F during exposure. FIG. 8 is a cross sectional view, similarto FIG. 7, schematically showing the chemical reaction in the film Fduring heating.

The film F consists of a photosensitive layer mainly composed of heatresistant binder, formed on the base material (substrate) made of PET.Further, a protective layer mainly consisting of heat resistant binderis formed on this photosensitive layer. The photosensitive layer ismixed with halogenated silver particles, silver behenate (Beh. Ag) as atype of organic acid silver, reducing agent and toning agent. Further, aback layer mainly composed of heat resistant binder is provided on theback of the base material.

When the laser light L is applied from the exposure section 120 to thefilm F at the time of exposure, halogenated silver particles are appliedto the area exposed to laser light L, as shown in FIG. 7, whereby alatent image is formed. In the meantime, the film F is heated by thedrum 14 of the development section 130 as described above. When thetemperature has exceeded the minimum temperature level for heatdevelopment, silver ion (Ag⁺) is supplied from silver behenate as shownin FIG. 8. The behenic acid having supplied forms toning agent andcomplex. Then the silver ion diffuses, and a silver image is consideredto be formed by chemical reaction through the action of reducing agent,with the exposed halogenated silver particle as a nucleus. As describedabove, the film F contains photosensitive halogenated silver particle,organic acid silver and silver ion reducing agent. It is not subjectedto heat development at the temperature below 40° C. This film issubjected to heat development at the minimum development temperatureabove 80° C. (e.g. at about 110° C.).

The present invention has been discussed with reference to anembodiment. It should be noted, however, that the present invention isnot restricted to this embodiment. It can be embodied in a great numberof variations without departing from the technological spirit and scopeof the invention claimed. For example, the intensity (amount) of laserlight is adjusted to compensate for density in the present embodiment.It is possible to control the heater temperature of the drum 14 of thedevelopment section 130, thereby adjusting the development temperature.It is also possible to adjust both the intensity (amount) of laser lightand development temperature.

(Second Embodiment of the Present Invention)

The following describes the functions characteristic of the secondembodiment of the present invention in the image processing apparatusgiven in FIG. 1. These functions are realized when controlled by thesoftware program (program) stored in advance in a predetermined storageapparatus such as flash ROM (not illustrated) in the image processingapparatus. The image processing apparatus of the present invention isprovided with the microcomputer (computer) containing a CPU (notillustrated). The following functions are performed by running of theprogram by such a computer.

FIG. 11 is a block diagram representing the functions of an imageprocessing apparatus for implementing the image processing method of thepresent invention. FIG. 12 is a flowchart representing the processing ofthe image processing apparatus given in FIG. 11.

As shown in FIG. 11, the image processing apparatus of the presentinvention comprises an exposure section 120 for executing the exposurestep, a development section 130 for executing the development step, ameasurement means 200 for executing the measurement step, a calibrationmeans 400 for executing the calibration step, a correction means 300 forexecuting the correction step, and a correction means for executing thecorrection step.

As shown in FIG. 12, test exposure data is exposed to light by theexposure section 120 and is developed by the development means 130(S61).

The test exposure data contains image signals for a wide variety ofvalues, and the image density conforming to the image signal are exposedand developed on the film in step S61.

The density of the film exposed by the exposure means 120 and developedby the development means 130 is measured by the measurement means 200(S62). In this case, the measured density is exposed and developed onthe film according to the image signal based on the test exposure data.

When the density is measured in step S62, a lookup table (LUT) iscreated in the calibration means 400 to associate the image signal tothe density in such a way that the density specified by the diagnosticimage data is reproduced on the film, based on the aforementioned testexposure data and density measured by the measurement means of the imageexposed and developed on the film according to the test exposure data(S63). To put it more specifically, this is done by specifying from thetest data the value of the image signal in forming on the film thedensity measured by the measurement means. The LUT, for example, can berepresented as shown in FIG. 13.

When the LUT has been created in step S63, the image of the diagnosticimage signal can be formed according to this LUT. Accordingly, thediagnostic image data is exposed by the exposure means 120 and developedby the development means 130 (S64). In formation of the image of thediagnostic image data in step S64, part of the film is exposed accordingto the same lookup table as that of the diagnostic image, concurrentlyas the diagnostic image is formed, in such a way that the predetermineddensity is reproduced. Part of the film where the image is formed refersto the area formed on the edge of the image formed area F2 such as F1 inthe film F given in FIG. 14. For example, an area of about 5×10 mm isused for this purpose.

It is preferred that evaluation is made to determine whether or not thetime elapsed is within the predetermined time period when counted fromthe time of creating he LUT in step S63. If more than the predeterminedtime has elapsed since the LUT was created, there may occur a deviationfrom the change of process in some cases.

If evaluation is made in step S65 to determine that the predeterminedtime has not elapsed, the density value for comparison is correctedaccording to the density value of the partial area exposed to reproducethe predetermined density, in the correction means 500 (S66). Thedensity value for comparison refers to the predetermined density at thetime of exposure to ensure that the predetermined density is produced inthe partial area of the film in step S4. It is preferred that thisdensity value for comparison be within the range from 1.0 to 2.0. Forexample, when the measured density value is 1.3 and the density valuefor comparison is 1.5, the density value for comparison subsequent tocorrection can be obtained, for example, from the following equation:

(Density value for comparison subsequent to correction)=Density valuefor comparison prior to correction)+(correction rate)×(measured densityvalue−density value for comparison)

In this case, a proper correction rate can be selected withconsideration given to the apparatus characteristics. If the correctionrate in this case is 0.5, then the density value for comparison to beobtained is 1.5+0.5×(1.5−1.3) according to the aforementioned equation.The density value for comparison subsequent to correction is 1.4, andthe difference from the predetermined density value is 0.1. Thus, thenext exposure condition is corrected in such a way that the density is0.1 higher (S67).

If evaluation is made in step S65 to determine that more than thepredetermined time has elapsed or after the processing in step S66 hasbeen completed, the exposure conditions in the exposure means 120 iscompensated by the compensation means 300 so that the density of thenext film will be optimized, based on the difference between themeasured density value obtained by measuring the density in the partialarea and the density value for comparison corresponding to thepredetermined amount of exposure (S67). In the compensation made in stepS67, if the measured density value is 1.8 and density value forcomparison is 1.5 for example, compensation is made for the exposureconditions to optimize the density of next film, in such a way that thedensity value will be lower by 0.3, which is the difference between thetwo density values.

Subsequent to the processing by the compensation means 300 in step S67,evaluation is made to determine whether there is diagnostic image dataor not (S68). If there is diagnostic image data, the system goes back tothe processing of exposure and development in step S64.

Every time the processing in step S64 through 68 is performed,correction by correction means 500 is repeated until evaluation is madeto determine that time elapsed is within the predetermined time periodwhen counted from the time of creating the LUT in step S65. This allowscorrection to be made in the appropriately suppressed amount ofcorrection, and prevents excessive compensation due to sudden changesfrom being made.

As described above, the present invention allows the patch densitysubsequent to creation of the LUT to be corrected automatically by thecorrection means 500. Thus, rise and fall of the density resulting fromchanges in characteristics between the patch portion and diagnosticimage formed area that may occur when replacing the film type, or therise and fall of the density resulting from the fluctuation of the imageprocessing apparatus can be corrected by automatic change of the defaultvalue of the density value for comparison—without depending on servicepersonnel—, thereby ensuring appropriate density of the finished film.

The following describes the functions as a third embodiment of thepresent invention in the image processing apparatus of FIG. 1, in termsof three embodiments. These functions are realized when controlled bythe software program (program) stored in advance in the predeterminedmemory apparatus such as the flash ROM (not illustrated) in the imageprocessing apparatus. The image processing apparatus of the presentinvention is provided with the microcomputer (computer) containing a CPU(not illustrated). The following functions are performed by running ofthe program by such a computer.

(Third Embodiment of the Present Invention—1)

FIG. 16 is a block diagram representing the function of the firstembodiment of the image processing apparatus.

FIG. 17 is a flowchart representing the processing by an imageprocessing apparatus given in FIG. 16.

As shown in FIG. 16, the image processing apparatus comprises anexposure means 120 for executing the exposure step, a development means130 for executing the development step, a densitometer 200 for executingthe measurement step, a density control means 600 for executing thedensity control step, a down time monitoring means 700 for executing thetime monitoring step and a compensation means 300 for executing thecompensation step.

As shown in FIG. 17, exposure and development are performed in theexposure means 120 and development means 130 (S71). To put it morespecifically, based on the image data, an image is formed as a latentimage on the film. At the same time, part of the film is exposed usingthe output calculated through the lookup table (LUT) with respect to thepredetermined amount of density, or specified exposure. Part of the filmwhere the image is formed refers to the area formed on the edge of theimage formed area F2 such as F1 in the film F given in FIG. 14. Forexample, an area of about 5×10 mm is used for this purpose. The usedlookup table (LUT) is obtained by calibration. Calibration is defined ascreation of a LUT to determine the relationship between image signal(specified density) and amount of exposure by obtaining the relationshipbetween amount of exposure and density on the film through the step ofmeasuring the density of a test image formed in advance. The LUT isrepresented in the form shown in FIG. 13.

The density of the partial area of the exposed and developed film ismeasured by the measurement means 200 (S72).

The density control means 600 controls the exposure section 120 and/ordevelopment section 130 so as to optimize the density of the next filmto be printed, based on the difference between the predetermined densityvalue for comparison and the measured density value, according to theresult of measuring the density by the measurement section (hereinafterreferred to as “patch data”) (S73). The result of measuring the densityrefers to the density of the partial area of a film (measured densityvalue) and the time of measuring that density. The predetermined densityis defined as the value predetermined for calculating the amount ofcontrol to offset the factors affecting the density of the finished filmsuch as the exposure means 120 and/or development means 130.

The density control means 600 uses two control methods, which will bedescribed below.

(First Method)

In the density control means 600, the change in density resulting fromthe exposure means 120 and/or development means 130 is offset bysubtracting the change of density based on the change in apparatuscharacteristics from the difference between the predetermined densityvalue for comparison and the measured density value. The change indensity based on the apparatus characteristics can be obtained as thedifference of density in the characteristic change models correspondingto each of the density measuring time and reference time. Further, thedensity control means 600 adjusts the output of the exposure means 120in the next image formation, based on the difference obtained after thedifference in density based on the characteristics change model has beensubtracted from the difference between the predetermined density valuefor comparison and the measured density value.

The image processing apparatus is subjected to changes in densityresulting from the with-time temperature change of the exposure means120 and/or development means 130.

So such characteristic changes can be formulated into a model ascharacteristic change model. The characteristic change model is themodel wherein change of characteristics with time is represented interms of correlation between time and density, in the exposure sectionand/or development section of the apparatus. It is preferred thatchanges in characteristics inherent to the apparatus be used for suchcharacteristic changes. This characteristic change model is exemplifiedin FIGS. 18(a) through (c). FIG. 18(a) shows an example of thecharacteristic change model of the exposure means 120. FIG. 18(b)indicates an example of the characteristic change model of thedevelopment means 130. FIG. 18(c) shows the characteristic change modelsof the exposure means 120 and development means 130. In FIG. 18(c), theportion of curve A indicates the characteristic change of a heatdevelopment apparatus as an example of the image processing apparatus;it shows the characteristics after processing is enabled (immediatelyafter getting into READY state) 15 through 30 minutes after power isturned on from the state where the system has conformed to theinstallation environment. The portion of curve B is determined by theexposure and development characteristics due to the rise of temperaturein the apparatus resulting from the next film processing.

Any one of the models given in FIGS. 18(a) through (c) can be used asthe characteristic change model in the present invention. Use of themodel of FIG. 18(c) is preferred from the viewpoint of conformance tothe actual apparatus.

(Second Method)

The density control means 600 provides a so-called FF (Feed Forward)control method for applying reverse bias to the characteristic changebased on the same characteristic change model as that of the firstmethod.

As described above, after processing of the step S73 by the densitycontrol means 600, the down time monitoring means 700 monitors the downtime (S74). When the down time is monitored by the down time monitoringmeans 700, the down time monitoring means 700 monitors the time when thepower is turned off after completion of the processing of the step S73by the density control means 600. For example, time is “0” if the poweris not turned off.

The compensation means 300 compensates for the control of the densitycontrol means 600, based on the down time monitored by the down timemonitoring means 700.

Compensation by the compensation means 300 will be described for thecases in the density control means 600 where control of the step S73 ismade based on the characteristic change model given in FIG. 19 and wherepower is turned on when “Ta” has elapsed after power is turned off atT1. In the characteristic change model in FIG. 19, the output of theexposure means 120 in the formation of the next image is adjusted insuch a way as to offset the difference (D2−D1) between the density valueat time T2 obtained by returning “αTa”—a value proportional to “Ta”equivalent to the down time—from time T1 when the power is turned off,and the density value at T1. When the change of density is to becontrolled based on the characteristic change of the apparatus by thesecond method in the density control means 600 after formation of thenext image, calculation is made on the assumption that the apparatus isturned on from T2.

In the control of the present invention, even if power is turned offfreely, the image of appropriate density can be outputted, without theneed of unwanted consumption of films through calibration at everyturning on of power, whereby energy is saved and a film is finished tohave an appropriate density without wasting a film.

(Third Embodiment of the Present Invention—2)

Density control compensation is performed based on the temperature whenpower is turned on, in contrast to the compensation by the compensationmeans for correcting density control based on the time when power isturned on, according to the first embodiment.

FIG. 20 is a block diagram representing the functions of the thirdembodiment—2 of the image processing apparatus for implementing theimage processing method of the present invention. Compensation fordensity control is performed based on the temperature when the power isturned on. FIG. 21 is a flowchart representing the processing of theimage processing apparatus given in FIG. 20.

As shown in FIG. 20, the image processing apparatus of the presentinvention comprises an exposure means 120 for executing the exposurestep, a development means 130 for executing the development step, ameasuring means 200 for executing the measurement step, a densitycontrol means 600 for executing the density control step, a temperaturedetection means 750 for executing the temperature detection step, and acompensation means 300 for executing the compensation set.

As shown in FIG. 20, exposure and development are performed in theexposure means 120 and development means 130 (SB1). To put it morespecifically, based on the image data, an image is formed as a latentimage on the film. At the same time, part of the film is exposed usingthe output calculated through the lookup table (LUT) with respect to thepredetermined amount of exposure or specified density. The LUT isrepresented in the form shown in FIG. 13, for example.

The density of the partial area of the exposed and developed film ismeasured by the measurement means 200 (S82).

The density control means 600 controls the exposure means 120 and/ordevelopment means 130 so as to optimize the density of the next film tobe printed, based on the difference between the predetermined densityvalue for comparison and the measured density value, according to theresult of measuring the density by the measurement section (hereinafterreferred to as “patch data”) (S83). To put it more specifically, thedensity control means 600 provides the same control as that of the thirdembodiment—1.

Upon completion of processing in step S83 by the density control means600, the temperature detection means 750 detects the temperature of atleast one position on the image processing apparatus when power isturned on (S84). The temperature detection means 750 detects thetemperature when power is turned off and is turned on upon completion ofthe processing in step S83 by the density control means 600. If power isturned off and power is not turned on, for example, the result oftemperature detection is not measured.

For the temperature detection means 750, it is preferred that thecooling/transporting section is provided with the temperature detectionmeans. In this case, the development means 130 is assumed to be providedwith a heating/transporting section and cooling/transporting section. Itis common practice that the temperature of the heating/transportingsection is kept almost constant as development temperature whenprocessing is enabled. The cooling/transporting section is affected bythe heating drum before the state of permitting processing is reached.However, if a predetermined amount of film is processed before power isturned on, there is thermal effect from this heated film, so thecooling/transporting section is affected by the temperature based on thetotal thermal influence when power is turned on. To put it another way,this is because the variation in the finished density is affected by thetemperature when the power of the cooling/transporting section is turnedon.

It is preferred that the temperature detection means 750 detect thetemperature of the exposure means 120. Changing characteristics of theexposure means 120 after the state of permitting processing is reachedare different according to the temperature when the power is turned on.This is because there is fluctuation in the amount of light reaching thefilm, due to fluctuation in the AOM characteristics and LD wavelengthand thermal expansion of the constituent parts of the optical system. Toput it another way, the variation in the finished density resulting fromthe exposure means 120 is affected by the temperature when power isturned on.

The compensation means 300 compensates for the control by the densitycontrol means 600, based on the temperature detected by the temperaturedetection means 750 (S85).

Compensation by the compensation means 300 can be obtained from thetable showing correlation between the temperature when power is turnedon as shown in FIGS. 22(a) and (b) and the amount of compensation forcharacteristic changes. FIG. 22(a) is a table representing thecorrelation of temperature characteristic changes resulting from theexposure means 120, and FIG. 22(b) is a table representing thecorrelation of temperature characteristic changes resulting from thedevelopment means 130. To put it more specifically, when the detectedtemperature when power is turned on is “Tb”, the output of the exposuremeans 120 in the formation of the next image is adjusted in such a wayas to offset the density corresponding to the temperature “Tb” obtainedfrom the temperature characteristic change in FIG. 22.

In the control of the present invention, even if power is turned offfreely, the image of appropriate density can be outputted, without theneed of unwanted consumption of films through calibration at everyturning on of power, whereby energy is saved and a film is finished tohave an appropriate density without wasting a film.

(Third Embodiment of the Present Invention—3)

The present embodiment includes compensation for density control to beconducted based on the time when power is turned off in the thirdembodiment—1, and compensation for density control to be conducted basedon the temperature when power is turned off in the third embodiment—2.

FIG. 23 is a block diagram representing the functions of the thirdembodiment of the image processing apparatus for implementing the imageprocessing method of the present invention. FIG. 24 is a flowchartrepresenting the processing of the image processing apparatus given inFIG. 23.

As shown in FIG. 23, the image processing apparatus of the presentinvention comprises an exposure means 120 for executing the exposurestep, a development means 130 for executing the development step, ameasuring means 200 for executing the measurement step, a densitycontrol means 600 for executing the density control step, a down timemonitoring means 700 for executing the down time monitoring process, atemperature detection means 750 for executing the temperature detectionstep, and a compensation means 300 for executing the compensation set.

As shown in FIG. 24, exposure and development are performed in theexposure means 120 and development means 130 (S91). To put it morespecifically, based on the image data, an image is formed as a latentimage on the film. At the same time, part of the film is exposed usingthe output calculated through the lookup table (LUT) with respect to thepredetermined amount of exposure or specified density. The LUT isrepresented in the form shown in FIG. 13, for example.

The density of the partial area of the exposed and developed film ismeasured by the measurement means 200 (S92).

The density control means 500 controls the exposure means 120 and/ordevelopment means 130 so as to optimize the density of the next film tobe printed, based on the difference between the predetermined densityvalue for comparison and the measured density value, according to theresult of measuring the density by the measurement means (hereinafterreferred to as “patch data”) (S93). To put it more specifically, thedensity control means 500 provides the same control as that of the thirdembodiment—1.

Upon completion of processing in step S93 by the density control means600, the down time monitoring means 700 monitors the down time for theimage processing apparatus (S94). When the down time monitoring means700 monitors the down time, it monitors the time when power is turnedoff upon completion of the step S93 by the density control means 600.For example, time is “0” if the power is not turned off.

The temperature detection means 750 detects the temperature of at leastone position on the image processing apparatus when power is turned on(S95). The temperature detection means 750 detects the temperature whenpower is turned off and is turned on upon completion of the processingin step S93 by the density control means 600. If power is turned off andpower is not turned on, for example, the result of temperature detectionis not measured.

For the temperature detection means 750, it is preferred that thecooling/transporting section is provided with the temperature detectionmeans. In this case, the development means 130 is assumed to be providedwith a heating/transporting section and cooling/transporting section. Itis common practice that the temperature of the heating/transportingsection is kept almost constant as development temperature whenprocessing is enabled. The cooling/transporting section is affected bythe heating drum before the state of permitting processing is reached.However, if a predetermined amount of film is processed before power isturned on, there is thermal effect from this heated film, so thecooling/transporting section is affected by the temperature based on thetotal thermal influence when power is turned on. To put it another way,this is because the variation in the finished density is affected by thetemperature when the power of the cooling/transporting section is turnedon.

It is preferred that the temperature detection means 750 detect thetemperature of the exposure means 120. Changing characteristics of theexposure means 120 after the state of permitting processing is reachedare different according to the temperature when the power is turned on.This is because there is fluctuation in the amount of light reaching thefilm, due to fluctuation in the AOM characteristics and LD wavelengthand thermal expansion of the constituent parts of the optical system. Toput it another way, the variation in the finished density resulting fromthe exposure means 120 is affected by the temperature when power isturned on.

The compensation means 300 compensates for the control by the densitycontrol means 600, based on down time monitored by the down timemonitoring means 700 and the temperature detected by the temperaturedetection means 750 (S96).

In compensation by the compensation means 300, the output of theexposure means 120 in the formation of the next image is adjusted insuch a way as to offset:

the difference in density (D2−D1) corresponding to the time “αTa”proportional to the down time obtained by the same method as that of thethird embodiment—1, based on the down time monitored by the down timemonitoring means 700, and the density obtained by the same method asthat of the third embodiment—2, based on the temperature detected by thetemperature detection means 750.

In the control of the present invention, even if power is turned offfreely, the image of appropriate density can be outputted, without theneed of unwanted consumption of films through calibration at everyturning on of power, whereby energy is saved and a film is finished tohave an appropriate density without wasting a film.

EFFECTS OF THE INVENTION

The density adjustment method of the present invention maintains theimage density of the same diagnostic image signals within the scope ofalmost the same density, even if fluctuation has occurred to thecharacteristics of the exposure and development systems or a differencehas occurred to the film characteristics in formation of a diagnosticimage.

The present invention provides an image processing apparatus, an imageprocessing method and a program wherein, even if there is anyfluctuation in an image processing apparatus or films of different types(film characteristics) are used, the density value for comparison isautomatically corrected using the measured density value of the patchportion immediately after calibration, whereby the default value isautomatically corrected and the finished film is adjusted to have anappropriate density.

The present invention further provides an image processing apparatus, animage processing method and a program wherein, even if power is turnedoff freely, the image of appropriate density can be outputted, withoutthe need of unwanted consumption of films through calibration at everyturning on of power, whereby energy is saved and a film is finished tohave an appropriate density without wasting a film.

What is claimed is:
 1. A density adjustment method for adjusting adensity of a diagnostic image formed on a film, comprising: exposing animage to form an latent image on the film based on test exposure dataand/or diagnostic image data; developing the latent image to form adeveloped image; measuring a density of the developed image; creating alookup table for relating the diagnostic image data and amount ofexposure so as to reproduce a density specified by the diagnostic imagedata, based on the test exposure data and a measured density of thedeveloped image formed on the film by the test exposure data; andcompensating by correcting at least one of an exposure condition in theexposing step and a development condition in the developing step toensure that the next film has the optimized density, based on thedifference between the measured density value obtained by exposing apartial area of the film with a prescribed exposure amount at the timeof forming the diagnostic image with the diagnostic image data and bymeasuring the density of the partial area of the film, and a densityvalue for comparison corresponding to the prescribed exposure amount;wherein, a density of a prescribed area, exposed by a specific exposureamount, in an image formed by an exposure based on the test exposuredata, is measured, and the measured value of the density is used as thedensity value for comparison; at the same time, the specific exposureamount is used as the prescribed exposure amount for exposing thepartial area of the film at the time of forming a diagnostic image. 2.The density adjustment method of claim 1, wherein the density of aprescribed area is within the range of 1.0 through 2.0.
 3. The densityadjustment method of claim 1, wherein a prescribed area, positioned atthe tip of the film, in the image formed by an exposure based on thetest exposure data is used for measuring the density of a prescribedarea.
 4. The density adjustment method of claim 1, wherein the partialarea of the film is positioned at the tip of the film, at the time offorming the diagnostic image.
 5. A density adjustment method foradjusting a density of a diagnostic image formed on a film, comprising:exposing an image to form an latent image on the film based on testexposure data and/or diagnostic image data; developing the latent imageto form a developed image; measuring a density of the developed image;creating a lookup table for relating the diagnostic image data andamount of exposure so as to form a density specified by the diagnosticimage data, based on the test exposure data and a measured density ofthe developed image formed on the film by the test exposure data; andcompensating by correcting at least one of an exposure condition in theexposing step and a development condition in the developing step toensure that the next film has the optimized density, based on thedifference between the measured density value obtained by exposing apartial area of the film with a prescribed exposure amount at the timeof forming the diagnostic image with the diagnostic image data and bymeasuring the density of the partial area of the film, and a densityvalue for comparison corresponding to the prescribed exposure amount;wherein, after creation of the lookup table, a specific exposure amountis obtained from the lookup table to get a predetermined density, thefilm is exposed by the specific exposure amount to form an image, adensity of the image is measured, and the density of the image is usedas the density for comparison, while the partial area of the film isexposed by the specific exposure amount at the time of forming asubsequent diagnostic image.
 6. The density adjustment method of claim5, the predetermined density is within the range of 1.0 through 2.0. 7.The density adjustment method of claim 5, wherein the density of theimage used as the density for comparison is a density of a predeterminedarea of an image positioned at the tip of the film.
 8. The densityadjustment method of claim 7, wherein the density of a predeterminedarea is an average of values having been measured several times.
 9. Thedensity adjustment method of claim 5, wherein when a condition changehas been made to at least one of the film, the developing step, theexposing step and the density measuring step, the lookup table iscreated, and the density value for comparison is set.
 10. The densityadjustment method of claim 9, the predetermined density is within therange of 1.0 through 2.0.
 11. The density adjustment method of claim 9,wherein the density of the image used as the density for comparison is adensity of a predetermined area of an image positioned at the tip of thefilm.
 12. The density adjustment method of claim 11, wherein the densityof a predetermined area is an average of values having been measuredseveral times.
 13. The density adjustment method of claim 9, wherein thedeveloping step is carried out by a heating section containing theheating member to heat the film, and by a cooling/transporting sectionfor transporting the heated film while cooling it, wherein when theheating member has been replaced and/or the cooling/transporting sectionhas been subjected to maintenance, the lookup table is created and thedensity value for comparison is set.
 14. The density adjustment methodof claim 1, wherein when a condition change has been made to at leastone of the film, the developing step, the exposing step and the densitymeasuring step, the lookup table is created, and the density value forcomparison is set.
 15. The density adjustment method of claim 14, thedensity of a prescribed area is within the range of 1.0 through 2.0. 16.The density adjustment method of claim 14, wherein a prescribed area,positioned at the tip of the film, in the image formed by an exposurebased on the test exposure data is used for measuring the density of aprescribed area.
 17. The density adjustment method of claim 14, whereinthe partial area of the film is positioned at the tip of the film, atthe time of forming the diagnostic image.
 18. The density adjustmentmethod of claim 14, wherein the developing step is carried out by aheating section containing the heating member to heat the film, and by acooling/transporting section for transporting the heated film whilecooling it, wherein when the heating member has been replaced and/or thecooling/transporting section has been subjected to maintenance, thelookup table is created and the density value for comparison is set. 19.An image processing apparatus for processing a diagnostic image,comprising: an exposure section for exposing an image to form an latentimage on the film based on test exposure data and diagnostic image data;a development section for developing the latent image to form adeveloped image; a measurement section for measuring a density of thedeveloped image; a calibration section for creating a lookup table forrelating the diagnostic image data and amount of exposure so as toreproduce a density specified by the diagnostic image data, based on thetest exposure data and a measured density of the developed image formedon the film by the test exposure data; and a compensation section forcorrecting at least one of an exposure condition in the exposure sectionand a development condition in the development section to ensure that anext film has an optimized density, based on the difference between themeasured density value obtained by exposing a partial area of the filmwith a prescribed exposure amount, which is obtained from the lookuptable so as to reproduce a predetermined density, at the time of formingthe diagnostic image with the diagnostic image data, and by measuringthe density of the partial area of the film, and a density value forcomparison corresponding to the prescribed exposure amount; wherein theimage processing apparatus further comprises a correction section forcorrecting the density value for comparison based on the measureddensity value, prior to correction by the compensation sectionsubsequent to creation of the lookup table by the calibration section.20. The image processing apparatus of claim 19, wherein the correctionsection corrects the density value for comparison based on the measureddensity value, at the time of forming an image within the predeterminedtime subsequent to creation of a lookup table by the calibrationsection.
 21. The image processing apparatus of claim 19, wherein thedensity value for comparison is within the range of 1.0 through 2.0. 22.An image processing method for processing a diagnostic image,comprising: exposing an image to form an latent image on the film basedon test exposure data and diagnostic image data; developing the latentimage to form a developed image; measuring a density of the developedimage; calibrating by creation of a lookup table for relating thediagnostic image data and amount of exposure so as to form a densityspecified by the diagnostic image data, based on the test exposure dataand a measured density of the developed image formed on the film by thetest exposure data; and compensating by correcting at least one of anexposure condition in the exposing step and a development condition inthe developing step to ensure that a next film has an optimized density,based on the difference between the measured density value obtained byexposing a partial area of the film with a prescribed exposure amount,which is obtained from the lookup table so as to reproduce apredetermined density, at the time of forming the diagnostic image withthe diagnostic image data, and by measuring the density of the partialarea of the film, and a density value for comparison corresponding tothe prescribed exposure amount; wherein the image processing methodfurther comprises a correcting step for correcting the density value forcomparison based on the measured density value, prior to correction bythe compensating step subsequent to creation of the lookup table by thecalibrating step.
 23. The image processing method of claim 22, whereinthe correcting step corrects the density value for comparison based onthe measured density value, at the time of forming an image within thepredetermined time subsequent to creation of a lookup table by thecalibrating step.
 24. The image processing method of claim 22, whereinthe density value for comparison is within the range of 1.0 through 2.0.25. A program for making a computer conduct an image processing methodby being incorporated in an image processing apparatus, the imageprocessing method comprising: exposing an image to form an latent imageon the film based on test exposure data and diagnostic image data;developing the latent image to form a developed image; measuring adensity of the developed image; calibrating by creation of a lookuptable for relating the diagnostic image data and amount of exposure soas to reproduce a density specified by the diagnostic image data, basedon the test exposure data and a measured density of the developed imageformed on the film by the test exposure data; and compensating bycorrecting at least one of an exposure condition in the exposing stepand a development condition in the developing step to ensure that a nextfilm has an optimized density, based on the difference between themeasured density value obtained by exposing a partial area of the filmwith a first prescribed exposure amount, which is obtained from thelookup table so as to reproduce a predetermined density, at the time offorming the diagnostic image with the diagnostic image data, and bymeasuring the density of the partial area of the film, and a densityvalue for comparison corresponding to the prescribed exposure amount;wherein the image processing method further comprises a correcting stepfor correcting the density value for comparison based on the measureddensity value, prior to correction by the compensating step subsequentto creation of the lookup table by the calibrating step.